U.S. patent application number 15/517932 was filed with the patent office on 2017-10-26 for fan case for an aircraft engine.
The applicant listed for this patent is FACC AG. Invention is credited to Walter FUERST, Ernst HAUGENEDER, Andreas HOELLRIGL, Konstantin HOREJSI, Boris STUBNA.
Application Number | 20170305117 15/517932 |
Document ID | / |
Family ID | 54539756 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170305117 |
Kind Code |
A1 |
FUERST; Walter ; et
al. |
October 26, 2017 |
FAN CASE FOR AN AIRCRAFT ENGINE
Abstract
The invention relates to a fan case for an aircraft engine in
the region of the fan thereof, comprising a plurality of
substantially cylindrically arranged fiber-reinforced plastic
layers that are joined together, wherein a reinforcement ply made
of glass fiber-reinforced plastic is disposed between an inner
layer and an outer layer. According to the invention, the
reinforcement ply consists of at least 20 plies of a glass
fiber-reinforced plastic, and that deformation layers are disposed
on both sides of the reinforcement ply, which deformation layers
have a lower strength than the reinforcement ply.
Inventors: |
FUERST; Walter; (Ried im
Innkreis, AT) ; HAUGENEDER; Ernst; (Ried im Innkreis,
AT) ; HOREJSI; Konstantin; (Ried im Innkreis, AT)
; STUBNA; Boris; (Ried im Innkreis, AT) ;
HOELLRIGL; Andreas; (Ried im Innkreis, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FACC AG |
Ried im Innkreis |
|
AT |
|
|
Family ID: |
54539756 |
Appl. No.: |
15/517932 |
Filed: |
October 9, 2015 |
PCT Filed: |
October 9, 2015 |
PCT NO: |
PCT/AT2015/050251 |
371 Date: |
April 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02T 50/672 20130101;
B32B 17/066 20130101; B32B 5/245 20130101; F04D 29/526 20130101;
F05D 2240/14 20130101; F01D 25/24 20130101; F01D 21/045 20130101;
B32B 2605/18 20130101; B32B 2250/05 20130101; F02C 7/04 20130101;
Y02T 50/60 20130101; B32B 17/04 20130101; B32B 3/12 20130101; B32B
17/10073 20130101; F02K 3/06 20130101; F05D 2300/603 20130101 |
International
Class: |
B32B 17/04 20060101
B32B017/04; B32B 17/06 20060101 B32B017/06; B32B 17/10 20060101
B32B017/10; F01D 21/04 20060101 F01D021/04; B32B 3/12 20060101
B32B003/12; F02C 7/04 20060101 F02C007/04; B32B 5/24 20060101
B32B005/24; F01D 25/24 20060101 F01D025/24 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 10, 2014 |
AT |
A 50723/2014 |
Claims
1. A fan case for an aircraft engine in a region of a fan thereof,
comprising a plurality of substantially cylindrically arranged
fiber-reinforced plastic layers that are joined together, wherein a
reinforcement ply made of a glass fiber-reinforced plastic is
disposed between an inner layer and an outer layer, wherein the
outer layer and the inner layer are made of a carbon
fiber-reinforced plastic, the reinforcement ply consists of at
least 20 plies of a glass fiber-reinforced plastic, that
deformation layers are disposed on both sides of the reinforcement
ply, which deformation layers have a lower strength than the
reinforcement ply, and that a deflection ring made of a material
having a higher strength than the deformation layers is disposed
between the inner layer and the reinforcement ply in the region of
the fan, wherein the deflection ring has a wedge-shaped
cross-section with an inclined surface oriented towards the
fan.
2. The fan case according to claim 1, wherein at least one
deformation layer is formed by a honeycomb structure.
3. The fan case according to claim 1, wherein at least one
deformation layer is formed by a foam material.
4. The fan case according to claim 1, wherein at least one
fastening flange is integrated within the outer layer.
5. The fan case according to claim 1, wherein on the inner layer an
abrasive layer made of a deformable material is disposed in the
region of the fan.
6. The fan case according to claim 5, wherein the abrasive layer is
made of a glass fiber-reinforced resin.
7. The fan case according to claim 1, wherein the deflection ring
is made of metal.
8. (canceled)
9. The fan case according to claim 1, wherein the deflection ring
is made of an aramid fiber-reinforced plastic.
10. (canceled)
11. (canceled)
12. The fan case according to claim 2, wherein at least one
deformation layer is formed by a foam material.
13. The fan case according to claim 2, wherein on the inner layer
an abrasive layer made of a deformable material is disposed in the
region of the fan.
14. The fan case according to claim 4, wherein on the inner layer
an abrasive layer made of a deformable material is disposed in the
region of the fan.
15. The fan case according to claim 4, wherein the deflection ring
is made of metal.
16. The fan case according to claim 5, wherein the deflection ring
is made of metal.
17. The fan case according to claim 4, wherein the deflection ring
is made of an aramid fiber-reinforced plastic.
18. The fan case according to claim 5, wherein the deflection ring
is made of an aramid fiber-reinforced plastic.
19. The fan case according to claim 15, wherein the deflection ring
is made of steel.
20. The fan case according to claim 16, wherein the deflection ring
is made of steel.
21. The fan case according to claim 2, wherein the deflection ring
is made of an aramid fiber-reinforced plastic.
22. The fan case according to claim 3, wherein the deflection ring
is made of an aramid fiber-reinforced plastic.
23. The fan case according to claim 7, wherein the deflection ring
is made of steel.
Description
[0001] The invention relates to a fan case and/or blower case for
an aircraft engine in the region of the fan thereof, comprising a
plurality of substantially cylindrically arranged fiber-reinforced
plastic layers that are joined together, wherein a reinforcement
ply made of a glass fiber-reinforced plastic is disposed between an
inner layer and an outer layer.
[0002] Fan cases of aircraft engines are used to prevent
destruction of the engine in the region of the fan and to protect
the passengers inside the aircraft from harm in case of damage when
a blade of the fan becomes disconnected. The materials for such fan
cases must be selected so that the high kinetic energy of the
disconnected fan blade can be absorbed. While metals, in particular
high-ductility steels or titanium alloys, were primarily used for
producing fan cases in the past, in recent times plastic has been
used for these aircraft components as well.
[0003] For example, US 2012/0148392 A1 describes a fan case made of
a fiber-reinforced plastic for an aircraft engine, wherein a
plurality of composite layers that are joined together are combined
with honeycomb structures disposed between them. A jacket made of
Kevlar.RTM. provides adequate protection in case of damage when a
fan blade becomes disconnected and enters the engine housing.
[0004] US 2008/0128073 A1 describes a fan case for aircraft engines
which is made of various plastic composites in a layered structure
using various fiber materials and combinations thereof.
[0005] GB 2 426 287 A describes a fan case in which metallic
structures are provided for meeting the safety requirements.
[0006] EP 2 096 269 A2 and EP 1 344 895 A2 describe engine linings
which are used for optimising the airflow within the engine, but do
not provide safety in case of damage when a fan blade breaks.
[0007] Many constructions of fan cases made of a fiber-reinforced
plastic are relatively labour-intensive in production and/or
require a multiplicity of material plies so the weight advantage
with respect to metal fan cases is no longer present or only
present to a very limited extent.
[0008] Therefore, the object of the present invention is to provide
a fan case for an aircraft engine which is as lightweight as
possible and safe at the same time. Drawbacks of known devices are
to be eliminated or at least reduced.
[0009] In order to achieve the object according to the invention,
the reinforcement ply consists of at least 20 plies of a glass
fiber-reinforced plastic and deformation layers are disposed on
both sides of the reinforcement ply, which deformation layers have
a lower strength than the reinforcement ply. The fan case
construction according to the invention is distinguished by at
least three layers being provided, namely the inner layer, the
reinforcement ply and the outer layer, for which special materials
are used to achieve the objects according to the invention, namely
the protection of the aircraft engine in case of damage, on the one
hand, and the retaining of a certain residual strength of the
aircraft engine for a safe landing, on the other hand. In the fan
case according to the invention, the two objects are achieved by
means of two different components so the materials of these
components may be adapted perfectly to the respective object. The
reinforcement ply made of a glass fiber-reinforced plastic in the
middle is mainly used to prevent a disconnected fan blade from
passing through the case and to withstand the impact. Corresponding
to this, glass fiber-reinforced plastic is used as it exhibits the
best properties with respect to an impact of a fan part. By
arranging at least 20 plies made of a glass fiber-reinforced
plastic, the usually required strengths are obtained. In aircraft
engines with particularly high speed and/or for smaller business
jets, a higher number of plies, for example 35 plies, may also be
required in order to meet the safety requirements. Due to the
position of the installation of the reinforcement ply with the
surrounding deformation layers within the fan case, said
reinforcement ply is also protected from damage, such as by falling
rocks, and the weight advantage may be obtained. On the other hand,
the residual strength required for a safe landing in case of damage
is mainly ensured by the outer layer of the fan case. Preferably,
the objective fan case is especially suited for aircraft engines
with very high speeds (>10000 revolutions per minute) in which
the kinetic energy of a disconnected part of the fan is
particularly high. Depending on the design, the weight of the fan
case may be reduced between 30% and 50% with respect to steel
constructions and by up to 10% with respect to titanium
constructions.
[0010] At least one deformation layer may be formed by a honeycomb
structure. Such a honeycomb structure is characterised by a
particularly low weight. In case of damage, the deformation layer
is deformed accordingly, and at least the outer layer of the fan
case is prevented from unacceptably high deformation.
[0011] At least one deformation layer may also be formed by a foam
material. By selecting adequate foam materials and possibly
combining it with the deformation layer consisting of a honeycomb
structure, the weight and/or deformability may be further improved.
Plastics such as acrylonitrile butadiene styrene copolymer (ABS),
polymethacrylimid (PMI) and the like are used as the foam
material.
[0012] Advantageously, at least one fastening flange is integrated
within the outer layer. By integrating at least one fastening
flange, in particular two fastening flanges (front and back), the
strength of the entire fan case is increased, since no joining
sites are required between the fastening flange and the outer
layer, while the mounting process is simplified.
[0013] On the inner layer of the fan case, an abrasive layer made
of a deformable material may be disposed in the region of the fan.
By using such an abrasive layer made of a deformable material, the
air gap between the fan of the aircraft engine and the inner layer
of the fan case may be further reduced since the fan blade having
the largest outer diameter cuts a corresponding shape into the
abrasive layer.
[0014] The abrasive layer may be made of a glass fiber-reinforced
resin or filled honeycomb cores. Such materials have proven
particularly useful and are sufficiently soft with respect to the
fan blades, which are usually made of titanium or titanium
alloys.
[0015] By disposing a deflection ring made of a material having a
higher strength than the deformation layers between the inner layer
and the reinforcement ply in the region of the fan, safety may be
improved in case of a breaking fan blade and/or material may be
saved in the inner layer and/or reinforcement layer while retaining
the same degree of safety. The deflection ring is used to deflect
the radially occurring forces, which are substantially punctual, to
the sides and thus counteract destruction of the fan case and/or
engine housing.
[0016] The deflection ring is preferably made of metal, in
particular steel. Due to the small size of the deflection ring with
respect to the entire fan case, the weight disadvantage it causes
is negligible.
[0017] Alternatively, the deflection ring may also be made of an
aramid fiber-reinforced plastic, for example Kevlar.RTM.. Such
fiber-reinforced plastics have a lower weight than metals, but are
also correspondingly more expensive.
[0018] If the deflection ring has a wedge-shaped cross-section with
an inclined surface oriented towards the fan, the radially
occurring force originating from a disconnected part of a fan blade
may be deflected and distributed to the sides so that,
consequently, the risk of destruction of the fan case or engine
housing and the hazard for the aircraft and the passengers may be
reduced.
[0019] The outer layer and the inner layer of the fan case are
preferably made of a carbon fiber-reinforced plastic. The outer
layer of the fan case, in particular, is formed by an accordingly
high number of layers of a carbon fiber-reinforced plastic in order
to provide sufficient stability to the aircraft engine in case of
damage and ensure a safe landing of the aircraft.
[0020] The invention is explained in more detail by means of an
exemplary embodiment below. Therein:
[0021] FIG. 1 shows an aircraft engine, partially in section, in an
arrangement having a fan case disposed in the region of the fan;
and
[0022] FIG. 2 shows a part of a fan case designed according to the
invention, illustrated in section.
[0023] FIG. 1 illustrates an aircraft engine 2, partially in
section, in an arrangement having a fan case 1 disposed in the
region of the fan 3. Typically, a fan case 1 consists of a
cylindrical jacket having fastening flanges and possible
strengthening ribs or the like integrated therein and/or attached
thereto. The fan case 1 is connected to the remaining engine
housing, which is again arranged on corresponding fastening
elements, usually wings.
[0024] FIG. 2 shows a part of a fan case 1 designed according to
the invention, illustrated in section. The fan case 1 includes an
inner layer 4 designed according to the aerodynamic requirements of
the aircraft engine 2 and an outer layer 5 as well as a
reinforcement ply 6 disposed between the inner layer 4 and the
outer layer 5, and deformation layers 7 disposed on both sides of
the reinforcement ply 6. Depending on the aircraft engine 2, the
reinforcement ply 6 is formed by at least 20 plies of a glass
fiber-reinforced plastic and is mainly used to withstand an impact
of a part of the fan 3 in case of damage. The deformation layers 7,
which may be formed by a honeycomb structure or suitable foam
materials or combinations thereof, are used to absorb the kinetic
energy originating from a disconnected part of the fan 3. The inner
layer 4 may be made of a carbon fiber-reinforced plastic. The outer
layer 5, which is mainly used to ensure residual strength of the
fan case 1 in case of damage and to allow a safe landing with the
damaged aircraft engine 2, is preferably made of a carbon
fiber-reinforced plastic as well.
[0025] To simplify the work for production and mounting, the
fastening flanges 8, 9 required for fastening the fan case 1 may be
integrated within the outer layer 5 and be produced in one
manufacturing process together with the outer layer 5. Due to the
functional separation of the reinforcement ply 6 and the outer
layer 5, tearing of the outer layer 5, in particular in the region
of the fastening flanges 8, 9, can be prevented in case of damage,
or at least the risk of damage can be reduced.
[0026] To reduce the air gap between the fan 3 and the inner layer
4, an abrasive layer 10 made of a deformable material may be
disposed in the region of the fan 3, with the fan blade having the
largest outer diameter cutting into the abrasive layer 10,
resulting in a vanishingly small air gap between the fan 3 and the
inner layer 4 and/or the abrasive layer 10. The abrasive layer 10
may be made of a glass fiber-reinforced resin or filled honeycomb
cores.
[0027] In the region of the fan 3, a deflection ring 11 made of a
material having a higher strength than the deformation layers 7 may
be disposed between the inner layer 4 and the reinforcement ply 6,
by which deflection ring 11 the radial forces occurring in case of
damage are deflected to the sides. The deflection ring 11 may be
made of metal, in particular steel, or also an aramid
fiber-reinforced plastic, for example Kevlar.RTM.. For an ideal
deflection of the radially acting forces, the deflection ring 11
may have a wedge-shaped cross-section with an inclined surface 12
oriented towards the fan 3, as illustrated.
[0028] At the rear end of the fan case 1, an extension element 13
may be disposed and preferably glued to the inner layer 4.
* * * * *